At what temperature does the solid start meltin
-20°C
0°C
20"
80°C

Answers

Answer 1

Answer:

0 C.

Explanation:


Related Questions

What is the chemical formula for the molecule modeled?
There are several ways to model a compound. One type
of model is shown.
A)СНО
B)C4H1102
C)C6H12O2
D)C6H90

Answers

Answer:

Tue answer is B - C4H1102

The chemical formula for the molecule modeled is C₆H₁₂O₂. Therefore, option C is correct.

What is a chemical formula ?

The term chemical formula is defined as the elements that form the compound and the numbers of atoms of each element in the smallest unit of that compound. Water is consist of hydrogen and oxygen in a 2:1 ratio. The chemical formula for water is H₂O.

There are 3 main types of chemical formulas that are empirical formula, molecular formula and structural formula.

Empirical formulas represent the simplest whole-number ratio of atoms in a compound, molecular formulas represent the number of each type of atom in a molecule, and structural formulas represent how the atoms in a molecule are bonded to each other.

In a given molecule modeled C₆H₁₂O₂ we see that, there are six atoms of carbon, 12 atoms of hydrogen and 2 atoms of oxygen.

Thus, option C is correct.

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0.5 g of salt is dissolved in 25 g of water. Calculate the percentage amount of salt in the solution.

Answers

Total mass = 0.5+25=25.5
0.5/25.5 x 100 = 1.96
Salt percentage = 1.96%

hi:) how to do 2(bi)?

Answers

Answer:

4 protons, 5 neutrons, 2 electrons

Explanation:

If you look at the numbers beside Be²⁺, the number 9 is the relative atomic mass and the number 4 is the proton (atomic) number. The relative atomic mass is the sum of the number of protons and the number of neutrons.

Number of protons= proton number.

Hence, number of protons= 4

Number of protons + neutrons= 9

4 + number of neutrons= 9

number of neutrons

= 9 -4

= 5

In an atom, the number of protons and electrons are the same since atoms are electrically neutral. But in an ion, the number of electrons is not equal to the number of protons since the atom gains/ loses electrons to form an ion. A positive sign means that electrons are given away.

Thus, Be gives away 2 electrons to form Be²⁺.

Original number of electrons= 4

Number of electrons in Be²⁺

= 4 -2

= 2

In summary, the number of protons and neutrons in an ion is the same as that of the atom. However, the number of electrons is not the same.

Answer:

Answer:

4 protons, 5 neutrons, 2 electrons

Explanation:

If you look at the numbers beside Be²⁺, the number 9 is the relative atomic mass and the number 4 is the proton (atomic) number. The relative atomic mass is the sum of the number of protons and the number of neutrons.

Number of protons= proton number.

Hence, number of protons= 4

Number of protons + neutrons= 9

4 + number of neutrons= 9

number of neutrons

= 9 -4

= 5

In an atom, the number of protons and electrons are the same since atoms are electrically neutral. But in an ion, the number of electrons is not equal to the number of protons since the atom gains/ loses electrons to form an ion. A positive sign means that electrons are given away.

Thus, Be gives away 2 electrons to form Be²⁺.

Original number of electrons= 4

Number of electrons in Be²⁺

= 4 -2

= 2

In summary, the number of protons and neutrons in an ion is the same as that of the atom. However, the number of electrons is not the same.

& BTW WOW U HAVE WHITENER TAPE !

hi:) why do acids produce hydrogen ions in aqueous solution?

Answers

Answer:

An acid produces hydrogen ions in aqueous solution because it reacts with the water molecules by giving a proton to them.

Explanation:

When hydrogen chloride gas dissolves in water to produce hydrochloric acid, the hydrogen chloride molecule gives a proton (a hydrogen ion) to a water molecule.

Answer:

Acids produce hydrogen ions in aqueous solution because they have a higher concentration of hydrogen ions than hydroxyl ions and that's the reason too why they have a lower pH.

Hope this helps.

An electron is in a region outside the nucleus. An electron
a) Is larger than a proton and has no charge
b) Has less mass than a proton and has a negative charge
c) Is smaller than a proton and has no charge
d) Has a positive charge

Answers

Answer:

b

Explanation:

electrons lie in the orbits of the atom. they are negatively charged and they are very small in size. they have very less mass than proton. ele tron has 1/1840 mass of proton.

In the reaction Fe2O3 + 3CO a 2Fe + 3CO2, 10 moles of solid iron and 15 moles of carbon dioxide are produced from 5 moles of iron (|||) oxide and 15 moles of carbon monoxide (CO). What is the ratio of carbon monoxide to solid iron

Answers

Answer:

Ratio is 3:2

3CO = 2Fe or 1.5 CO = 1 Fe

Explanation:

Fe2O3 + 3CO = 2Fe + 3CO2

Fe2O3 = Iron (|||) oxide

CO = Carbon monoxide

Fe = Solid Iron

CO2 = Carbon dioxide

Excellent is already balanced.

10 Moles Fe and 15 Moles of CO2

5 Moles Fe2O3 + 15 Moles 3CO = 10 Moles Fe + 15 Moles 3CO2

What is the ratio of carbon monoxide to solid iron

Ratio is 3:2 or 1.5 CO = 1 Fe

An electrical company charges 15 p per unit of energy (kWh).
Calculate the cost of running a 500 W freezer for a day. Show your working.

Answers

Answer:

180 p

Explanation:

Energy refers to the capacity of doing work.

Amount charged by an electrical company = 15 p per unit of energy (kWh)

As 1 W = 1000 kW,

[tex]500W=\frac{500}{1000}kW=0.5\,kW[/tex]

Also, 1 day = 24 hours.

Cost of running a 500 W freezer = 0.5 kW freezer for 1 hour = [tex]15\times 0.5=7.5\,p[/tex]

Therefore,

cost of running a 0.5 kW freezer for a day ( 24 hours ) = [tex]7.5\times 24=180\,p[/tex]

Amount charged by an electrical company = 15 p per unit of energy (kWh)

As 1 W = 1000 kW,

[tex]500W=\frac{500}{1000}kW=0.5\,kW[/tex]

Also, 1 day = 24 hours.

Cost of running a 500 W freezer = 0.5 kW freezer for 1 hour = [tex]15\times 0.5=7.5\,p[/tex]

Therefore,

cost of running a 0.5 kW freezer for a day ( 24 hours ) = [tex]7.5\times 24=180\,p[/tex]

Classify the following as an element, compound, homogeneous mixture, or heterogeneous


mixture: salt water

A. Element
B. Compound
C. Homogeneous mixture
D. Heterogenous mixture

Answers

The answer is D. Heterogeneous mixture

Is Raisin Bran cereal with milk homogeneous

Answers

Answer:

no

Explanation:

Homogeneous means that the substance looks uniform throughout. This means that all of it looks the same (ex. juice or water). Because you can see the different parts of raisin bran cereal with milk it is not homogeneous, it is heterogeneous.

What forces does an electrically charge object experience because of its charge?

Answers

Answer:

electric force and newtons law

Explanation:

if the freezing point of a substance is 68°C, what is its melting point?

Answers

The melting point will be the freezing point times .14

The melting point of the substance has been [tex]\rm 68^\circ C[/tex].

The freezing point has been defined as the temperature above to which the substance exists in the liquid state, while below which the substance exist in the solid state.

Freezing point and melting point

The melting point has been the temperature at which the solid starts to convert into the liquid state. The melting point and freezing point for the substances has been the same temperature.

Thus, the melting point of the substance whose freezing point has been [tex]\rm 68^\circ C[/tex] has been [tex]\rm 68^\circ C[/tex].

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The Law of Conservation of Matter
states that matter cannot be created
or
a. enlarged
B. changed
C. broken
D. destroyed

Answers

D. Destroyed
“A fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system.”

Answer:

The law of conservation of matter indicates that matter cannot be created nor destroyed.

So D Destroyed

What are the 3 critical components of an electromagnet and what purpose do they each serve?

Answers

Answer:

A source of electricity, a wire coil, and an iron core  

Explanation:

An electromagnet has three critical components:

1. A source of electricity

This is often a battery.

It generates the electric current that produces the magnetic field.  

2. A wire coil

The wire carries the electric current.

Stacking the wire into loops makes a stronger magnetic field.

The more loops in the coil, the stronger the field.

3. An iron core

An iron core greatly increases the strength of the magnetic field within it and at its ends.

Write a word equation and symbol equation (including state symbols)
for the reaction of calcium chloride with sodium hydroxide

Answers

Answer:

Explanation:

Calcium chloride reacts with NaOH to produce the Calcium hydroxide

CaCl2 + 2NaOH   ----> 2NaCl + Ca(OH)2

CAN I PLEASE GET SOME HELP PLEASE PLEASE HELP ME I WOULD APPRECIATE IT AND THANK YOU!! WICH of the following is an expression of Avogadro's law (k=constant) A)V=kn B)V=k/n C)nV=k D)V=k no

Answers

Answer:

Vn = k

Explanation:

[tex]Vn = k[/tex]

From the web :

Avogadro's Law is stated mathematically as follows: Vn=k, where V is the volume of the gas, n is the number of moles of the gas, and k is a proportionality constant

Avogadro's Law is stated mathematically as follows: Vn=k, where V is the volume of the gas, n is the number of moles of the gas, and k is a proportionality constant.

What is Avagrado's law?

According to Avogadro's Law, all gases have an identical number of molecules in an equal volume at a given temperature and pressure. Amedeo Avogadro, an Italian chemist and physicist, first described the law in 1811.

At 0 °C and 1 abm pressure, the molar volume of all ideal gases is 22.4 litres.  If a gas's temperature and pressure remain constant, its volume will also grow as its amount increases.

If a gas's pressure and temperature are both constant, its volume falls as its volume of gas does. Every time you blow a balloon up, you demonstrate Avogadro's Law.

Therefore, Avogadro's Law is stated mathematically as follows: Vn=k, where V is the volume of the gas, n is the number of moles of the gas, and k is a proportionality constant.

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What state of matter has indefinite volume and is compressible?

a. Gas

B. Liquid

C. Both Liquid and Gas

D. Solid

Answers

The answer is A. Gas

What is the energy of light with a wavelength of 652 nm? (The speed of light in a vacuum is 3.00 x 108 m/s, and Planck's constant is 6.626 x 10-34 J·s.)
O A 3.05 x 10-²⁸ j
O B. 3.28 x 10¹⁸ j
O C. 3.05 x 10-¹⁹ j
D. 3.28 x 10²⁷ j

A and C have negative exponents pleas help me​

Answers

Answer:

C. 3.05 x 10⁻¹⁹ J

Explanation:

Given;

wavelength of the light, λ = 652 nm = 652 x 10⁻⁹ m

speed of light, c = 3.00 x 10⁸ m/s

Planck's constant, h = 6.626 x 10⁻³⁴J·s

Energy of electromagnetic wave is calculated as;

E = hf

where;

f is frequency of the light wave

f = c / λ

[tex]E = hf = h\frac{c}{\lambda} \\\\E = \frac{hc}{\lambda} \\\\E = \frac{6.626*10^{-34}*3*10^8}{652*10^{-9}} \\\\E = 3.05*10^{-19} \ J[/tex]

Therefore, the energy of the light is 3.05 x 10⁻¹⁹ J

The correct option is "C"

C. 3.05 x 10⁻¹⁹ J

Answer:

Option C. 3.05 x 10¯¹⁹ J

Explanation:

Step 1:

Data obtained from the question.

wavelength (λ) 652 nm = 652x10^–9m

Velocity of light (v) = 3.00x10^8 m/s

Planck's constant (h) = 6.626x10^-34J·s

Step 2:

Determination of the frequency of the light.

The frequency can be obtained as follow

v = λf

3x10^8 = 652x10^–9 x f

Divide both side by 652x10^–9

f = 3x10^8 / 652x10^–9

f = 4.6x10^14s¯¹

Step 3:

Determination of the energy of the light wave.

This can be obtained as follow:

Planck's constant (h) = 6.626x10^-34J·s

Frequency (f) = 4.6x10^14s¯¹

Energy (E) =..?

E = hf

E = 6.626x10^-34 x 4.6x10^14s¯¹

E = 3.05 x 10¯¹⁹ J

) carbon + oxygen = _____________
E) calcium carbonate = ______________ + _________________
F) carbon + hydrogen = ____________
G) carbon + hydrogen + oxygen = ______________
H) water = ___________ + ___________
I) Iron + sulphur = _______________
J) magnesium + oxygen = ________________
M) magnesium oxide + water = ___________________
O) carbon monoxide + oxygen = ______________

Answers

Answer:

d)carbon(iv)oxide/carbon(ii)oxide

e)Calcium,carbon,oxygen

f)carnonhydride

g)Carbonhydrate

h)hydrogen+oxygen

I)Iron sulphide

j)Magnesiumoxide

m)magnesium hydroxide+hydrogen gas

d)carbon dioxide

The conversation of cyclopropane to propene in the gas phase is a first order reaction with a rate constant of 6.7x10-⁴s-¹. a) if the initial concentration of cyclopropane was 0.25M , what is the concentration after 8.8min?b) how long (in min) will it take for the concentration of cyclopropane to decrease from 0.25M to 0.15M?

Answers

Answer: a)  The concentration after 8.8min is 0.17 M

b) Time taken for the concentration of cyclopropane to decrease from 0.25M to 0.15M is 687 seconds.

Explanation:

Expression for rate law for first order kinetics is given by:

[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process  

a) concentration after 8.8 min:

[tex]8.8\times 60s=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{a-x}[/tex]

[tex]\log\frac{0.25}{a-x}=0.15[/tex]

[tex]\frac{0.25}{a-x}=1.41[/tex]

[tex](a-x)=0.17M[/tex]

b) for concentration to decrease from 0.25M to 0.15M

[tex]t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{0.15}\\\\t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\times 0.20[/tex]

[tex]t=687s[/tex]

As much sugar as will dissolve is added to hot water. The water is then
cooled, and all of the sugar remains dissolved in the solution. Which term
describes the final sugar solution?
O A. Nonsaturated
O B. Saturated
C. Unsaturated
O D. Supersaturated

Answers

The answer is C because it says describe the final sugar and C is unsaturated and in the problem it says as much as sugar will dissovle .

A moving train comes to a stop at the station. What happened to

make the train change motion?

1)The train experienced an unbalanced force.


2)The train experienced a balanced force.


3)The train would stop with or without forces.


4)The train does not experience forces acting on it.

Answers

the second one “The train experienced a balanced force.

Based on the Lewis/electron dot representation
of the two atoms, predict the ratio of metal
cationic (+) atom to nonmetal anionic (-) atom in the compound

Answers

Answer:

A. 1:3

Explanation:

If we look at the ions shown in the image attached to the question, we will notice that we have aluminum (Al^3+), a trivalent ion combining with the iodide ion (I^-).

Aluminum can easily give out its three outermost electrons to three atoms of iodine. If aluminum gives out its three electrons, it achieves the stable octet structure. Iodine atoms have seven electrons in their outermost shell. They only need one more electrons to complete their octet. This one electron can be gotten by the combination of three iodine atoms with one atom of aluminum. One electron each is transferred from the aluminum atom to each iodine atom to form AlI3 with a ratio of 1:3.

Lewis dot structure is a diagrammatic representation of valence electrons in an atom of a molecule.

The ratio of the cations to anions in the given compound is 1:3.

In the given figure, Aluminum has 3 electrons, which can be donated to iodine. Aluminum has atomic number 13, this means that if the element donates three electrons then it will attain a stable electronic configuration.

In the Iodine atom, each iodine needs only one electron to complete its octet. Thus, three atoms of iodine will be required to gain electrons from aluminum.

Thus, the ratio cation to the anion is 1:3.

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What is the name of the body part that passes messages
from the sensory neurons to the brain?
o Lungs
O Nerve Cells
o Brain
o Stimulus please help me thanks

Answers

The answer would be nerve cells. Hope that helps you!

what element must combine with the metal for oxidation to take place?

Answers

lithium with oxygen
Lithium with oxygen

When we move from the bottom to the top of the periodic table:
Electronegativity increases and ionisation energy decreases
Both electronegativity and ionisation energy decreases
Both electronegativity and ionisation energy increases
They remain the same

Answers

Answer:

When we move from the bottom to the top of the periodic table:

Both electronegativity and ionisation energy increases.

Explanation:

The ionization energy I is the energy needed to start an electron to a gaseous atom, isolated and in a fundamental state. The electrons are attracted to the nucleus, so it is necessary to provide energy to start them. You should keep in mind that the electrons of the last layer are always lost, because they are the weakest attracted to the nucleus.

In a group, the ionization energy increases upwards because when passing from one element to the bottom, it contains one more layer of electrons. Therefore, the valence layer electrons, being further away from the nucleus, will be less attracted to it and it will cost less energy to pluck them.

On the other hand, electonegativity is defined as the ability of an element to attract electrons that link it to another element.

When descending within the same group, the atomic radius increases and the ionization energy decreases, indicating that the electrons are less attracted to the nucleus and therefore the electronegativity decreases from top to bottom.

What’s one renewable energy resource that can be used instead of fossil fuels ?

Answers

Answer:

Solar Energy & Wind Energy

Explanation:

These are renewable energy and can be used used in replacement for fossil fuels.

PLS MARK ME AS BRAINLIEST!!

Horned animals have different sizes of horns. The size of their horns can affect their ability to
compete for a mate or provide protection from predators,
What is this an example of?
overproduction
O variation
survival of fit individuals

Answers

Answer:

survival of fit individuals

Explanation:

I believe its survival of fit individuals because the animals with different horns are going to be able to find a mate or provide better depending on their horn and its kind of like natural selection in the sense those who have genetically better (??) horns are more likely to survive.  Hope it helps but it might be a little bit of a confusing explanation.

Answer:

variation

Explanation:

survival of the fittest, is more like, "out of 3 people only 1 makes it"

^ so the other guy is wrong.

10.Conduction is the method of heat transfer in solids but not liquids and gases. Why?
(1 Point)
Finiter your​

Answers

Answer:

Conduction only happens when the object is a solid, because conduction happens in objects that are closely, with molecules that are closely packed together, and have a definite shape. Since, in liquids and gases, the shape is not definite nor do they have closely packed molecules., conduction does not take place in them

Classify the following as an element, compound, homogeneous mixture, or heterogeneous

mixture:

Hydrogen (H2)

A. Element
B. Compound
C. Homogenous mixture
D. Heterogenous mixture

Answers

Hydrogen (H2) is an element.

A compound is a molecule that contains at least two different elements.

How are electrons and positrons the same, and how are they different?

Answers

Answer:

A positron is the antimatter counterpart of an electron (also called anti-electron). ... The spin, a type of angular momentum carried by the electron and positron, is the same for both. However, the electron and positron have the opposite charge. The electron has a negative charge, and the positron has positive charge.

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